Carbohydrate-protein template synthesized high mannose loading gold nanoclusters: A powerful fluorescence probe for sensitive Concanavalin A detection and specific breast cancer cell imaging

Diagnosis and treatment status of inoperable locally advanced breast cancer and the application value of inorganic nanomaterials

Locally advanced breast cancer (LABC) is a heterogeneous group of breast cancer that accounts for 10-30% of breast cancer cases. Despite the ongoing development of current treatment methods, LABC remains a severe and complex public health concern around the world, thus prompting the urgent requirement for innovative diagnosis and treatment strategies. The primary treatment challenges are inoperable clinical status and ineffective local control methods. With the rapid advancement of nanotechnology, inorganic nanoparticles (INPs) exhibit a potential application prospect in diagnosing and treating breast cancer. Due to the unique inherent characteristics of INPs, different functions can be performed via appropriate modifications and constructions, thus making them suitable for different imaging technology strategies and treatment schemes. INPs can improve the efficacy of conventional local radiotherapy treatment. In the face of inoperable LABC, INPs have proposed new local therapeutic methods and fostered the evolution of novel strategies such as photothermal and photodynamic therapy, magnetothermal therapy, sonodynamic therapy, and multifunctional inorganic nanoplatform. This article reviews the advances of INPs in local accurate imaging and breast cancer treatment and offers insights to overcome the existing clinical difficulties in LABC management.

Fabrication of Au nanoclusters confined on hydroxy double salt-based intelligent biosensor for on-site monitoring of urease and its inhibitors

Sensitive and convenient sensing of urease and its inhibitors is exceptionally urgent in clinical diagnosis and new drug development. In this study, the gold nanoclusters (AuNCs) and hydroxyl double salt (HDS) were composited by a simple confinement effect to prepare highly fluorescent AuNCs@HDS composites to monitor urease and its drug inhibitors. HDS was used as a matrix to confine AuNCs (AuNCs@HDS), facilitating the emission intensity of AuNCs. However, acidic conditions (low pH) can disrupt the structure of HDS to break the confinement effect, and quench the fluorescence of AuNCs. Therefore, a sensing platform for pH-related enzyme urease detection was constructed based on the sensitive response of AuNCs@HDS to pH. This sensing platform had a linear response range of 0.5-22.5 U/L and a low limit of detection (LOD) of 0.19 U/L for urease. Moreover, this sensing platform was also applied to monitor urease inhibitors and urease in human saliva samples. Additionally, a portable hydrogel kit combined with a smartphone was developed for urease detection to achieve portable, low-cost, instrument-free, and on-site monitoring of urease.

Harnessing aptamers for the biosensing of cell surface glycans - A review

Cell surface glycans (CSGs) are essential for cell recognition, adhesion, and invasion, and they also serve as disease biomarkers. Traditional CSG recognition using lectins has limitations such as limited specificity, low stability, high cytotoxicity, and multivalent binding. Aptamers, known for their specific binding capacity to target molecules, are increasingly being employed in the biosensing of CSGs. Aptamers offer the advantage of high flexibility, small size, straightforward modification, and monovalent recognition, enabling their integration into the profiling of CSGs on living cells. In this review, we summarize representative examples of aptamer-based CSG biosensing and identify two strategies for harnessing aptamers in CSG detection: direct recognition based on aptamer-CSG binding and indirect recognition through protein localization. These strategies enable the generation of diverse signals including fluorescence, electrochemical, photoacoustic, and electrochemiluminescence signals for CSG detection. The advantages, challenges, and future perspectives of using aptamers for CSG biosensing are also discussed.

Sugar-based carboxamidoquinoline conjugate for sensing Cu2+ and Au3+ ions in water through different binding modes and real application

A simple water-soluble carboxamidoquinoline derivative of glucofuranose 1 exhibited reversible selectivity toward Cu2+ and Au3+ ions in different binding modes. Sensor 1 is an example of a dual sensor for identifying copper and gold ions in the water medium. Sensor 1 exhibited excellent selection ability and sensitivity for Cu2+ and Au3+ ions rather than several metal ions and anions with a wide pH range (5-10). The association constants for both ions were determined to be 3.58 × 104 M-1 and 1.84 × 104 M-1, respectively. The 1:1 binding chemistry of the complexes was verified from the Job method and again validated through mass spectra. Sensor 1 can detect Cu2+ and Au3+ ions at very low concentrations, such as 0.014 μM for Cu2+ and 0.058 μM for Au3+. The different sensing strategies of sensor 1 towards Cu2+ and Au3+ were manifested from the photophysical properties of sensor 2 with metal ions, FT-IR spectra, and theoretical (DFT) observations. The useful relevance of the sensor for Cu2+ and Au3+ ions was tested in different water samples.

Versatile MXene composite probe-mediated homogeneous electrochemiluminescence biosensor with integrated signal transduction and near-infrared modulation strategy for concanavalin A detection

Based on the highly specific interaction between concanavalin A (Con A) and glucose (Glu), a competitive electrochemiluminescence (ECL) biosensor was constructed for ultrasensitive detection of Con A. Nanocomposites with excellent electrocatalytic and photothermal properties were obtained by covalently bonding zinc oxide quantum dots (ZnO QDs) to vanadium carbide MXene (V2C MXene) surfaces. The modification of ZnO QDs hinders the aggregation of V2C MXene and increases the catalytic activity of oxygen reduction reaction, thus amplifying the luminol cathodic emission. In addition, the excellent photothermal performance of the V2C MXene-ZnO QDs can convert light energy into heat energy under the irradiation of 808 nm near infrared laser, thus increasing the temperature of the reaction system and accelerating the electron transfer process to realize the synergistic amplified homogeneous ECL system. This innovative work not only enriches the fundamental research on multifunctional MXene nanomaterials for biosensing, but also provides an effective strategy for ECL signal amplification.

Perspectives of different colour-emissive nanomaterials in fluorescent ink, LEDs, cell imaging, and sensing of various analytes

In the past 2 decades, multicolour light-emissive nanomaterials have gained significant interest in chemical and biological sciences because of their unique optical properties. These materials have drawn much attention due to their unique characteristics towards various application fields. The development of novel nanomaterials has become the pinpoint for different application areas. In this review, the recent progress in the area of multicolour-emissive nanomaterials is summarized. The different emissions (white, orange, green, red, blue, and multicolour) of nanostructure materials (metal nanoclusters, quantum dots, carbon dots, and rare earth-based nanomaterials) are briefly discussed. The potential applications of different colour-emissive nanomaterials in the development of fluorescent inks, light-emitting diodes, cell imaging, and sensing devices are briefly summarized. Finally, the future perspectives of multicolour-emissive nanomaterials are discussed.

The Recent Development of Multifunctional Gold Nanoclusters in Tumor Theranostic and Combination Therapy

The rising incidence and severity of malignant tumors threaten human life and health, and the current lagged diagnosis and single treatment in clinical practice are inadequate for tumor management. Gold nanoclusters (AuNCs) are nanomaterials with small dimensions (≤3 nm) and few atoms exhibiting unique optoelectronic and physicochemical characteristics, such as fluorescence, photothermal effects, radiosensitization, and biocompatibility. Here, the three primary functions that AuNCs play in practical applications, imaging agents, drug transporters, and therapeutic nanosystems, are characterized. Additionally, the promise and remaining limitations of AuNCs for tumor theranostic and combination therapy are discussed. Finally, it is anticipated that the information presented herein will serve as a supply for researchers in this area, leading to new discoveries and ultimately a more widespread use of AuNCs in pharmaceuticals.

Title: Advances of Gold Nanoclusters for Bioimaging

Gold nanoclusters (AuNCs) have become a promising material for bioimaging detection because of their tunable photoluminescence, large Stokes shift, low photobleaching, and good biocompatibility. Last decade, great efforts have been made to develop AuNCs for enhanced imaging contrast and multimodal imaging. Herein, an updated overview of recent advances in AuNCs was present for visible fluorescence (FL) imaging, near-infrared fluorescence (NIR-FL) imaging, two-photon near-infrared fluorescence (TP-NIR-FL) imaging, computed tomography (CT) imaging, positron emission tomography (PET) imaging, magnetic resonance imaging (MRI), and photoacoustic (PA) imaging. The justification of AuNCs applied in bioimaging mentioned above applications was discussed, the performance location of different AuNCs were summarized and highlighted in an unified parameter coordinate system of corresponding bioimaging, and the current challenges, research frontiers, and prospects of AuNCs in bioimaging were discussed. This review will bring new insights into the future development of AuNCs in bio-diagnostic imaging.

A universal strategy of glyconanoparticle preparation using a bifunctional linker for lectin sensing and cell imaging

Glyconanoparticles (G-NPs), biofunctional nanomaterials that can fully combine the unique properties of nanoparticles (NPs) with the bioactivities of carbohydrates, have become an appealing nanoplatform in analytical chemistry and biomedical research. However, there is currently a lack of an efficient and universal method for facile immobilization of reducing carbohydrates on NPs while maintaining their structure integrity, greatly limiting the preparation and application of G-NPs. Herein, a new and universal strategy for preparing carbohydrate-functionalized gold nanoclusters (Au NCs) was developed by using S-(3-(methoxyamino)propyl) thioacetate (MPTA) as a new bifunctional linker. MPTA with an N-methoxyamine group (-NHOMe) and a thioacetyl group (-SAc) was synthesized by a two-step strategy and then grafted onto Au NCs by an efficient click reaction. Subsequently, reducing carbohydrates could be readily immobilized onto MPTA-functionalized Au NCs (MPTA-Au NCs) by a reducing end ring-closure reaction under mild conditions. The obtained G-NPs showed average size of 1.9 ± 0.42 nm and strong fluorescence at 610 nm. Carbohydrates grafted on G-NPs still retained their structure integrity and specific recognition ability toward their receptor proteins. Notably, the affinity between G-NPs and proteins was increased by 1300 times compared with free carbohydrates with an association constant of (1.47 ± 0.356) × 10⁶ M⁻¹. The prepared fluorescent G-NPs were also successfully applied to lectin sensing and targeted breast cancer cell imaging with good performance. These results indicated that the intact immobilization of reducing carbohydrates (whether naturally or chemically accessed) on NPs could be easily achieved using MPTA, providing a simple, efficient, and universal strategy for G-NP preparation.

Selectivity of 1-O-Propargyl-d-Mannose Preparations

Thanks to their ability to bind to specific biological receptors, mannosylated structures are examined in biomedical applications. One of the most common ways of linking a functional moiety to a structure is to use an azide-alkyne click reaction. Therefore, it is necessary to prepare and isolate a propargylated mannose derivative of high purity to maintain its bioactivity. Three known preparations of propargyl-α-mannopyranoside were revisited, and products were analysed by NMR spectroscopy. The preparations were shown to yield by-products that have not been described in the literature yet. Our experiments showed that one-step procedures could not provide pure propargyl-α-mannopyranoside, while a three-step procedure yielded the desired compound of high purity.

Design of a Ratiometric Plasmonic Biosensor for Herceptin Detection in HER2-Positive Breast Cancer

Breast cancer is the most common cause of cancer death in women; therefore, its early detection and treatment are crucial. To achieve this goal, we designed an optical sensor based on direct interaction of trastuzumab [Herceptin (HER)], a monoclonal antibody used to treat HER2-positive breast cancer, with plasmonic nanoparticles. Surface-modified gold nanoparticles (AuNPs) have gained considerable attention in biosensing techniques over the last years, which actuated these nanoparticles to the heart of various biosensing notions. We have exploited the localized surface plasmon resonance (LSPR) of gold nanoparticles to determine HER in human serum. AuNPs were decorated with negatively charged citrate ions, yielding enhanced direct-surface interaction with HER antibodies. The AuNPs are mixed with silver nanoparticles (AgNPs) in an optimized ratio to increase selectivity and sensitivity further. AuNPs detect the HER antibodies using LSPR, whereas AgNPs help monitor interferences' effect on the sensing media. The three effective factors in HER sensing, including the nanoparticle ratio, temperature, and pH were optimized via response surface methodology (RSM) based on the central composite design (CCD). The sensor's response toward HER was achieved in the linear range of 0.5 × 10^-7 to 40 × 10^-7 M with the detection limit of 3.7 × 10^-9 M and relative standard deviation (RSD) less than 5%. The selectivity of the LSPR sensor was assessed by monitoring its response toward HER in the presence of other biological molecules with similar physicochemical properties. Rapid response time (less than 1 min), selectivity, and the simplicity of the developed LSPR-based sensor are the key advantages of the developed sensor.

TEMPO-Cellulose Nanocrystal-Capped Gold Nanoparticles for Colorimetric Detection of Pathogenic DNA

Nanocellulose-assisted gold nanoparticles are considered promising materials for developing eco-friendly diagnostic tools for biosensing applications. In this study, we synthesized 2,2,6,6-tetramethylpiperidin-1-piperidinyloxy (TEMPO)-oxidized cellulose nanocrystal (TEMPO-CNC)-capped gold nanoparticles (AuNPs) for the colorimetric detection of unamplified pathogenic DNA oligomers of methicillin-resistant Staphylococcus aureus. The fabricated TEMPO-CNC-AuNPs (TC-AuNPs) were characterized using UV-visible spectroscopy, transmission electron microscopy, atomic force microscopy, and dynamic light scattering. The average diameter of the synthesized AuNPs was approximately 30 nm. The aqueous solution of TC-AuNPs was stable and exhibited an absorption peak at 520 nm. The chemical interaction between TC-AuNPs and the surface charge of the target and non-target DNA determined the colorimetric differences under ionic conditions. A dramatic color change (red → blue) was observed in the TC-AuNP solution with the target DNA under ionic conditions due to the aggregation of AuNPs. However, no observable color change occurred in the TC-AuNP solution with the non-target DNA under similar conditions owing to the better shielding effects of the charged moieties. The colorimetric detection limit of the TC-AuNPs was demonstrated to be as low as 20 fM pathogenic DNA. Therefore, the use of TEMPO-oxidized CNC-capped AuNPs is efficient and straightforward as a biosensor for the colorimetric detection of pathogenic DNA.